Tổng quan hệ thống GMDSS phục vụ TKCN. Năm 1979,Tổ chức Hàng Hải quốc tế (International Maritime Organization IMO) đã tổ chức hội nghị về vấn đề tìm kiếm và cứu nạn trên biển. ... Hệ thống mới được tự động hóa và sử dụng sóng vô tuyến trái đất và vệ tinh cho báo động cấp cứu và các thông tin theo sa
Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C An Inmarsat-B installation uses a long wire antenna omnidirectional antenna parabolic dish 1m dipole C As a safety precaution when working aloft near a transmitter antenna, ensure that the antenna insulators are clean and transmitter switched of transmitter switched of main fuses removed and connect antenna to earth transmitter is switched to the standby condition antenna is disconnected from the transmitter and main fuses removed B The safety loops on a long wire antenna allows the antenna to resonate on several diferent bands allows leakage of excess electromagnetic energy to earth support the antenna should increased tension cause the antenna to snap prevent electric shock to those working on deck C A safety precaution when working aloft near a transmitter antenna, is to disable the transmitter by removing the supply fuses lock the frequency on 2182 kHz with transmitter on low power and J3E ensure the transmitter is in the standby position only ensure the transmission mode is at H3E A The weak link is included on a safety loop to provide a low breaking strain in event of collision/grounding etc high breaking strain in event of collision/grounding etc high resistance path to electromagnetic energy low resistance path to electromagnetic energy A Insulators are included in an antenna system to provide a high resistance path to earth low resistance path to earth high breaking strain low breaking strain A Safety loops are fitted to wire transmitting antennas to isolate the antenna from earth prevents the antenna falling in case of increased tension act as an essential radiation element of the antenna prevent excessive electromagnetic leakage A A small omnidirectional antenna is used with Inmarsat-B Inmarsat-M Inmarsat-F77 D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi A B C D Dap an Cau hoi Inmarsat-C A A safety precaution when working aloft is to ensure the transmitter is safe by switching to the standby position and earthing the antenna switching to the standby position and selecting low power connect the antenna and switch to low power removing fuses and connecting the antenna to earth A Insulators on a ship’s antenna system are used to ofer a high resistance path to earth for electromagnetic energy prevent electric shock to those working on deck allow the antenna to be tuned to several frequencies ofer a low resistance path to earth for electromagnetic energy A An Inmarsat-C installation uses a short wire antenna parabolic dish antenna directional antenna omnidirectional antenna A A safety precaution when working aloft near a transmitter antenna, the antenna should be switched to the transmitter on standby for testing earth as a safety precaution and remove transmitter supply fuses the transmitter (low power) and tuned to 2182 kHz the transmitter (low power) and tuned to 2187.5 kHz A Inmarsat Fleet 77 uses a directional antenna whip antenna omnidirectional antenna long wire antenna A A safety precaution when working aloft is to lock the frequency on 2182 kHz with transmitter on low power and H3E ensure the transmission mode is at H3E ensure the transmitter is in the standby position only disable the transmitter by removing the supply fuses A The antenna used by an Inmarsat F 77 is long-wire directional omnidirectional whip A Inmarsat-C satellite equipment should be fitted with a A B C D Dap an to 1.5 metre dipole antenna unidirectional antenna within a protective dome to metre whip antenna omnidirectional antenna within a protective dome A ... the antenna switching to the standby position and selecting low power connect the antenna and switch to low power removing fuses and connecting the antenna to earth A Insulators on a ship’s antenna... antenna parabolic dish antenna directional antenna omnidirectional antenna A A safety precaution when working aloft near a transmitter antenna, the antenna should be switched to the transmitter... power) and tuned to 2187.5 kHz A Inmarsat Fleet 77 uses a directional antenna whip antenna omnidirectional antenna long wire antenna A A safety precaution when working aloft is to lock the frequency